Revert "Begin implementing WGC CaptureFrame"

This reverts commit e820cef5340610b9beebbcb63868743b95b97fcd.

Reason for revert: Breaks downstream client. I will investigate and
get back with a suggestion to fix.

Original change's description:
> Begin implementing WGC CaptureFrame
>
> This change introduces the design that will allow us to deliver frames
> synchronously to callers despite the Windows.Graphics.Capture APIs being
> inherently asynchronous.
>
> We achieve this by having WindowCapturerWinWgc create and maintain a
> WgcCaptureSession object for each window that it is asked to capture a
> frame for. The capture session object will be the class that actually
> uses the WGC APIs, and it will store the frames it receives in a frame
> pool and deliver them via GetMostRecentFrame.
>
> The next CL will add the necessary functionality to the
> WgcCaptureSession class.
>
> Bug: webrtc:9273
> Change-Id: I44e164f4874503d8ccc8e6a210e74f9c8458f6c4
> Reviewed-on: https://webrtc-review.googlesource.com/c/src/+/184220
> Commit-Queue: Austin Orion <auorion@microsoft.com>
> Reviewed-by: Tommi <tommi@webrtc.org>
> Cr-Commit-Position: refs/heads/master@{#32240}

TBR=mbonadei@webrtc.org,jamiewalch@chromium.org,tommi@webrtc.org,auorion@microsoft.com

Change-Id: I114944357ce5be7d1e2da817703dc95d544aa99a
No-Presubmit: true
No-Tree-Checks: true
No-Try: true
Bug: webrtc:9273
Reviewed-on: https://webrtc-review.googlesource.com/c/src/+/186045
Reviewed-by: Mirko Bonadei <mbonadei@webrtc.org>
Commit-Queue: Mirko Bonadei <mbonadei@webrtc.org>
Cr-Commit-Position: refs/heads/master@{#32248}